This circuit was originally designed to measure capacitance with an ICL7107 but can be used with other digital modules. The circuit is from Electronics Now magazine from November 1996.
This circuit was found in ancient American documentation. Equivalent operational amplifiers can be...
Found on Popular Electronics this circuit has variations found throughout this site and section....
This 10 kHz filter is based on a 741 operational amplifier. The circuit is from Electronics Now...